checkpoint messages, half-complete RPC

internal/gotelem/rpc.go

@@ -1,12 +1,14 @@
 package gotelem
 
 import (
+	"errors"
+	"math/rand"
 	"net"
+	"sync"
 
 	"github.com/tinylib/msgp/msgp"
 )
 
-
 // the target architecture is a subscribe function that
 // takes a can FILTER. Then the server will emit notifications.
 // that contain new can packets as they come in.
@@ -19,8 +21,7 @@ import (
 // since reflected code can be more complex under the hood.
 
 // ServiceFunc is a RPC service handler.
-type ServiceFunc func(params msgp.Raw) (res msgp.MarshalSizer, err error)
-
+type ServiceFunc func(params msgp.Raw) (res msgp.Raw, err error)
 
 // RPCConn is a single RPC communication pair.
 type RPCConn struct {
@@ -31,15 +32,29 @@ type RPCConn struct {
 	// indicates what messages we've used.
 	// TODO: use a channel to return a response?
 	// TODO: lock with mutex
-	ct map[uint32]struct{}
+	ct rpcConnTrack
 }
 
 // Call intiates an RPC call to a remote method and returns the
 // response, or the error, if any.
 // TODO: determine signature
 // TODO: this should block?
-func (rpc *RPCConn) Call(method string, params msgp.Marshaler) {
+func (rpc *RPCConn) Call(method string, params msgp.Marshaler) (msgp.Raw, error) {
 
+	// TODO: error handling.
+	rawParam, _ := params.MarshalMsg([]byte{})
+
+	id, cb := rpc.ct.Claim()
+
+	req := NewRequest(id, method, rawParam)
+
+	w := msgp.NewWriter(rpc.conn)
+	req.EncodeMsg(w)
+
+	// block and wait for response.
+	resp := <-cb
+
+	return resp.Result, &resp.Error
 }
 
 // Notify initiates a notification to a remote method. It does not
@@ -48,6 +63,12 @@ func (rpc *RPCConn) Call(method string, params msgp.Marshaler) {
 // problem.
 func (rpc *RPCConn) Notify(method string, params msgp.Marshaler) {
 	// TODO: return an error if there's a local problem?
+	rawParam, _ := params.MarshalMsg([]byte{})
+
+	req := NewNotification(method, rawParam)
+
+	w := msgp.NewWriter(rpc.conn)
+	req.EncodeMsg(w)
 
 }
 
@@ -73,9 +94,10 @@ func (rpc *RPCConn) Serve() {
 
 	var rawmsg msgp.Raw = make(msgp.Raw, 0, 4)
 
+	for {
 		rawmsg.DecodeMsg(msgReader)
 
-	rpcIntf, err := parseRPC(rawmsg)
+		rpcIntf, _ := parseRPC(rawmsg)
 
 		switch rpcObject := rpcIntf.(type) {
 		case Request:
@@ -85,7 +107,12 @@ func (rpc *RPCConn) Serve() {
 		case Notification:
 			go rpc.dispatchNotif(rpcObject)
 		case Response:
-		// TODO: return response to caller.
+			cbCh, err := rpc.ct.Clear(rpcObject.MsgId)
+			if err != nil {
+				// TODO: scream
+			}
+			cbCh <- rpcObject
+		}
 	}
 }
 
@@ -118,3 +145,94 @@ func (rpc *RPCConn) dispatchNotif(req Notification) {
 	}
 	// no need for response.
 }
+
+// RPCConntrack is a request-response tracker that is used to connect
+// the response to the appropriate caller.
+type rpcConnTrack struct {
+	ct map[uint32]chan Response // TODO: change the values of the map for callbacks.
+	mu sync.RWMutex
+}
+
+// Get attempts to get a random mark from the mutex.
+func (c *rpcConnTrack) Claim() (uint32, chan Response) {
+	// TODO: make this threadsafe.
+	var val uint32
+	for {
+
+		newVal := rand.Uint32()
+		// collision is *rare* - so we just try again.
+		// I hope to god you don't saturate this tracker.
+		c.mu.RLock()
+		if _, exist := c.ct[newVal]; !exist {
+			val = newVal
+			c.mu.RUnlock()
+			break
+		}
+		c.mu.RUnlock()
+	}
+
+	// claim it
+	// the channel should be buffered. We only expect one value to go through.
+	// so the size is fixed.
+	ch := make(chan Response, 1)
+	c.mu.Lock()
+	c.ct[val] = ch
+	c.mu.Unlock()
+
+	return val, ch
+}
+
+// Clear deletes the connection from the tracker and returns the channel
+// associated with it. The caller can use the channel afterwards
+// to send the response.
+func (c *rpcConnTrack) Clear(val uint32) (chan Response, error) {
+	// TODO: get a lock
+	c.mu.RLock()
+	ch, ok := c.ct[val]
+	c.mu.RUnlock()
+	if !ok {
+		return nil, errors.New("invalid msg id")
+	}
+	c.mu.Lock()
+	delete(c.ct, val)
+	c.mu.Unlock()
+	return ch, nil
+}
+
+// Next, we define some helper generic functions that can be used to make
+// implementing a msg wrapper easier.
+
+type msgpackObject interface {
+	msgp.Decodable
+	msgp.Encodable
+	msgp.MarshalSizer
+	msgp.Unmarshaler
+}
+
+// MakeService is a generic wrapper function. It takes a function with the signature
+// of func(T msgpObject)(R msgpObject, error) where T and R can be *concrete* types.
+// and returns a new function that handles conversion to/from msgp.Raw.
+// the function returned can be used by the RPCConn as a handler function.
+func MakeService[T, R msgpackObject](fn func(T) (R, error)) func(msgp.Raw) (msgp.Raw, error) {
+	return func(p msgp.Raw) (msgp.Raw, error) {
+		// decode the raw data into a new underlying type.
+		var params T
+		// TODO: handler errors
+		_, err := params.UnmarshalMsg(p)
+
+		if err != nil {
+			return nil, err
+		}
+
+		// now, call the function fn with the given params, and record the value.
+
+		resp, err := fn(params)
+
+		if err != nil {
+			return nil, err
+		}
+
+		return resp.MarshalMsg([]byte{})
+
+	}
+}

internal/gotelem/rpc_msg.go

@@ -18,7 +18,6 @@ const (
 	NotificationType RPCType = 2
 )
 
-
 // the messagepack RPC spec requires that the RPC wire formts are ordered arrays,
 // aka tuples. we can use msgp options to make them tuple automatically,
 // based on the order they are declared. This makes the order of these
@@ -74,6 +73,14 @@ type Notification struct {
 	Params  msgp.Raw `msg:"params,allownil"`
 }
 
+func NewNotification(method string, params msgp.Raw) *Notification {
+	return &Notification{
+		msgtype: 2,
+		Method:  method,
+		Params:  params,
+	}
+}
+
 // todo: should these be functions instead, since they're arrays? and we need to determine the type beforehand.
 
 func getMsgType(b []byte) RPCType {
@@ -95,7 +102,6 @@ func getMsgType(b []byte) RPCType {
 	return RPCType(vtype)
 }
 
-
 // parseRPC takes a raw message and decodes it based on the first value
 // of the array (the type). It returns the decoded object. Callers
 // can use a type-switch to determine the type of the data.
@@ -126,14 +132,12 @@ func parseRPC(raw msgp.Raw) (interface{}, error) {
 // RPCError is a common RPC error format. It is basically a clone of the
 // JSON-RPC error format. We use it so we know what to expect there.
 
-
 //msgp:tuple RPCError
 type RPCError struct {
 	Code int
 	Desc string
 }
 
-
 // Converts a go error into a RPC error.
 func MakeRPCError(err error) *RPCError {
 	if err == nil {
@@ -144,3 +148,7 @@ func MakeRPCError(err error) *RPCError {
 		Desc: err.Error(),
 	}
 }
+
+func (r *RPCError) Error() string {
+	return r.Desc
+}

internal/gotelem/rpc_msg_gen.go

@@ -0,0 +1,494 @@
+package gotelem
+
+// Code generated by github.com/tinylib/msgp DO NOT EDIT.
+
+import (
+	"github.com/tinylib/msgp/msgp"
+)
+
+// DecodeMsg implements msgp.Decodable
+func (z *Notification) DecodeMsg(dc *msgp.Reader) (err error) {
+	var zb0001 uint32
+	zb0001, err = dc.ReadArrayHeader()
+	if err != nil {
+		err = msgp.WrapError(err)
+		return
+	}
+	if zb0001 != 2 {
+		err = msgp.ArrayError{Wanted: 2, Got: zb0001}
+		return
+	}
+	z.Method, err = dc.ReadString()
+	if err != nil {
+		err = msgp.WrapError(err, "Method")
+		return
+	}
+	err = z.Params.DecodeMsg(dc)
+	if err != nil {
+		err = msgp.WrapError(err, "Params")
+		return
+	}
+	return
+}
+
+// EncodeMsg implements msgp.Encodable
+func (z *Notification) EncodeMsg(en *msgp.Writer) (err error) {
+	// array header, size 2
+	err = en.Append(0x92)
+	if err != nil {
+		return
+	}
+	err = en.WriteString(z.Method)
+	if err != nil {
+		err = msgp.WrapError(err, "Method")
+		return
+	}
+	err = z.Params.EncodeMsg(en)
+	if err != nil {
+		err = msgp.WrapError(err, "Params")
+		return
+	}
+	return
+}
+
+// MarshalMsg implements msgp.Marshaler
+func (z *Notification) MarshalMsg(b []byte) (o []byte, err error) {
+	o = msgp.Require(b, z.Msgsize())
+	// array header, size 2
+	o = append(o, 0x92)
+	o = msgp.AppendString(o, z.Method)
+	o, err = z.Params.MarshalMsg(o)
+	if err != nil {
+		err = msgp.WrapError(err, "Params")
+		return
+	}
+	return
+}
+
+// UnmarshalMsg implements msgp.Unmarshaler
+func (z *Notification) UnmarshalMsg(bts []byte) (o []byte, err error) {
+	var zb0001 uint32
+	zb0001, bts, err = msgp.ReadArrayHeaderBytes(bts)
+	if err != nil {
+		err = msgp.WrapError(err)
+		return
+	}
+	if zb0001 != 2 {
+		err = msgp.ArrayError{Wanted: 2, Got: zb0001}
+		return
+	}
+	z.Method, bts, err = msgp.ReadStringBytes(bts)
+	if err != nil {
+		err = msgp.WrapError(err, "Method")
+		return
+	}
+	bts, err = z.Params.UnmarshalMsg(bts)
+	if err != nil {
+		err = msgp.WrapError(err, "Params")
+		return
+	}
+	o = bts
+	return
+}
+
+// Msgsize returns an upper bound estimate of the number of bytes occupied by the serialized message
+func (z *Notification) Msgsize() (s int) {
+	s = 1 + msgp.StringPrefixSize + len(z.Method) + z.Params.Msgsize()
+	return
+}
+
+// DecodeMsg implements msgp.Decodable
+func (z *RPCError) DecodeMsg(dc *msgp.Reader) (err error) {
+	var zb0001 uint32
+	zb0001, err = dc.ReadArrayHeader()
+	if err != nil {
+		err = msgp.WrapError(err)
+		return
+	}
+	if zb0001 != 2 {
+		err = msgp.ArrayError{Wanted: 2, Got: zb0001}
+		return
+	}
+	z.Code, err = dc.ReadInt()
+	if err != nil {
+		err = msgp.WrapError(err, "Code")
+		return
+	}
+	z.Desc, err = dc.ReadString()
+	if err != nil {
+		err = msgp.WrapError(err, "Desc")
+		return
+	}
+	return
+}
+
+// EncodeMsg implements msgp.Encodable
+func (z RPCError) EncodeMsg(en *msgp.Writer) (err error) {
+	// array header, size 2
+	err = en.Append(0x92)
+	if err != nil {
+		return
+	}
+	err = en.WriteInt(z.Code)
+	if err != nil {
+		err = msgp.WrapError(err, "Code")
+		return
+	}
+	err = en.WriteString(z.Desc)
+	if err != nil {
+		err = msgp.WrapError(err, "Desc")
+		return
+	}
+	return
+}
+
+// MarshalMsg implements msgp.Marshaler
+func (z RPCError) MarshalMsg(b []byte) (o []byte, err error) {
+	o = msgp.Require(b, z.Msgsize())
+	// array header, size 2
+	o = append(o, 0x92)
+	o = msgp.AppendInt(o, z.Code)
+	o = msgp.AppendString(o, z.Desc)
+	return
+}
+
+// UnmarshalMsg implements msgp.Unmarshaler
+func (z *RPCError) UnmarshalMsg(bts []byte) (o []byte, err error) {
+	var zb0001 uint32
+	zb0001, bts, err = msgp.ReadArrayHeaderBytes(bts)
+	if err != nil {
+		err = msgp.WrapError(err)
+		return
+	}
+	if zb0001 != 2 {
+		err = msgp.ArrayError{Wanted: 2, Got: zb0001}
+		return
+	}
+	z.Code, bts, err = msgp.ReadIntBytes(bts)
+	if err != nil {
+		err = msgp.WrapError(err, "Code")
+		return
+	}
+	z.Desc, bts, err = msgp.ReadStringBytes(bts)
+	if err != nil {
+		err = msgp.WrapError(err, "Desc")
+		return
+	}
+	o = bts
+	return
+}
+
+// Msgsize returns an upper bound estimate of the number of bytes occupied by the serialized message
+func (z RPCError) Msgsize() (s int) {
+	s = 1 + msgp.IntSize + msgp.StringPrefixSize + len(z.Desc)
+	return
+}
+
+// DecodeMsg implements msgp.Decodable
+func (z *RPCType) DecodeMsg(dc *msgp.Reader) (err error) {
+	{
+		var zb0001 int
+		zb0001, err = dc.ReadInt()
+		if err != nil {
+			err = msgp.WrapError(err)
+			return
+		}
+		(*z) = RPCType(zb0001)
+	}
+	return
+}
+
+// EncodeMsg implements msgp.Encodable
+func (z RPCType) EncodeMsg(en *msgp.Writer) (err error) {
+	err = en.WriteInt(int(z))
+	if err != nil {
+		err = msgp.WrapError(err)
+		return
+	}
+	return
+}
+
+// MarshalMsg implements msgp.Marshaler
+func (z RPCType) MarshalMsg(b []byte) (o []byte, err error) {
+	o = msgp.Require(b, z.Msgsize())
+	o = msgp.AppendInt(o, int(z))
+	return
+}
+
+// UnmarshalMsg implements msgp.Unmarshaler
+func (z *RPCType) UnmarshalMsg(bts []byte) (o []byte, err error) {
+	{
+		var zb0001 int
+		zb0001, bts, err = msgp.ReadIntBytes(bts)
+		if err != nil {
+			err = msgp.WrapError(err)
+			return
+		}
+		(*z) = RPCType(zb0001)
+	}
+	o = bts
+	return
+}
+
+// Msgsize returns an upper bound estimate of the number of bytes occupied by the serialized message
+func (z RPCType) Msgsize() (s int) {
+	s = msgp.IntSize
+	return
+}
+
+// DecodeMsg implements msgp.Decodable
+func (z *Request) DecodeMsg(dc *msgp.Reader) (err error) {
+	var zb0001 uint32
+	zb0001, err = dc.ReadArrayHeader()
+	if err != nil {
+		err = msgp.WrapError(err)
+		return
+	}
+	if zb0001 != 3 {
+		err = msgp.ArrayError{Wanted: 3, Got: zb0001}
+		return
+	}
+	z.MsgId, err = dc.ReadUint32()
+	if err != nil {
+		err = msgp.WrapError(err, "MsgId")
+		return
+	}
+	z.Method, err = dc.ReadString()
+	if err != nil {
+		err = msgp.WrapError(err, "Method")
+		return
+	}
+	err = z.Params.DecodeMsg(dc)
+	if err != nil {
+		err = msgp.WrapError(err, "Params")
+		return
+	}
+	return
+}
+
+// EncodeMsg implements msgp.Encodable
+func (z *Request) EncodeMsg(en *msgp.Writer) (err error) {
+	// array header, size 3
+	err = en.Append(0x93)
+	if err != nil {
+		return
+	}
+	err = en.WriteUint32(z.MsgId)
+	if err != nil {
+		err = msgp.WrapError(err, "MsgId")
+		return
+	}
+	err = en.WriteString(z.Method)
+	if err != nil {
+		err = msgp.WrapError(err, "Method")
+		return
+	}
+	err = z.Params.EncodeMsg(en)
+	if err != nil {
+		err = msgp.WrapError(err, "Params")
+		return
+	}
+	return
+}
+
+// MarshalMsg implements msgp.Marshaler
+func (z *Request) MarshalMsg(b []byte) (o []byte, err error) {
+	o = msgp.Require(b, z.Msgsize())
+	// array header, size 3
+	o = append(o, 0x93)
+	o = msgp.AppendUint32(o, z.MsgId)
+	o = msgp.AppendString(o, z.Method)
+	o, err = z.Params.MarshalMsg(o)
+	if err != nil {
+		err = msgp.WrapError(err, "Params")
+		return
+	}
+	return
+}
+
+// UnmarshalMsg implements msgp.Unmarshaler
+func (z *Request) UnmarshalMsg(bts []byte) (o []byte, err error) {
+	var zb0001 uint32
+	zb0001, bts, err = msgp.ReadArrayHeaderBytes(bts)
+	if err != nil {
+		err = msgp.WrapError(err)
+		return
+	}
+	if zb0001 != 3 {
+		err = msgp.ArrayError{Wanted: 3, Got: zb0001}
+		return
+	}
+	z.MsgId, bts, err = msgp.ReadUint32Bytes(bts)
+	if err != nil {
+		err = msgp.WrapError(err, "MsgId")
+		return
+	}
+	z.Method, bts, err = msgp.ReadStringBytes(bts)
+	if err != nil {
+		err = msgp.WrapError(err, "Method")
+		return
+	}
+	bts, err = z.Params.UnmarshalMsg(bts)
+	if err != nil {
+		err = msgp.WrapError(err, "Params")
+		return
+	}
+	o = bts
+	return
+}
+
+// Msgsize returns an upper bound estimate of the number of bytes occupied by the serialized message
+func (z *Request) Msgsize() (s int) {
+	s = 1 + msgp.Uint32Size + msgp.StringPrefixSize + len(z.Method) + z.Params.Msgsize()
+	return
+}
+
+// DecodeMsg implements msgp.Decodable
+func (z *Response) DecodeMsg(dc *msgp.Reader) (err error) {
+	var zb0001 uint32
+	zb0001, err = dc.ReadArrayHeader()
+	if err != nil {
+		err = msgp.WrapError(err)
+		return
+	}
+	if zb0001 != 3 {
+		err = msgp.ArrayError{Wanted: 3, Got: zb0001}
+		return
+	}
+	z.MsgId, err = dc.ReadUint32()
+	if err != nil {
+		err = msgp.WrapError(err, "MsgId")
+		return
+	}
+	var zb0002 uint32
+	zb0002, err = dc.ReadArrayHeader()
+	if err != nil {
+		err = msgp.WrapError(err, "Error")
+		return
+	}
+	if zb0002 != 2 {
+		err = msgp.ArrayError{Wanted: 2, Got: zb0002}
+		return
+	}
+	z.Error.Code, err = dc.ReadInt()
+	if err != nil {
+		err = msgp.WrapError(err, "Error", "Code")
+		return
+	}
+	z.Error.Desc, err = dc.ReadString()
+	if err != nil {
+		err = msgp.WrapError(err, "Error", "Desc")
+		return
+	}
+	err = z.Result.DecodeMsg(dc)
+	if err != nil {
+		err = msgp.WrapError(err, "Result")
+		return
+	}
+	return
+}
+
+// EncodeMsg implements msgp.Encodable
+func (z *Response) EncodeMsg(en *msgp.Writer) (err error) {
+	// array header, size 3
+	err = en.Append(0x93)
+	if err != nil {
+		return
+	}
+	err = en.WriteUint32(z.MsgId)
+	if err != nil {
+		err = msgp.WrapError(err, "MsgId")
+		return
+	}
+	// array header, size 2
+	err = en.Append(0x92)
+	if err != nil {
+		return
+	}
+	err = en.WriteInt(z.Error.Code)
+	if err != nil {
+		err = msgp.WrapError(err, "Error", "Code")
+		return
+	}
+	err = en.WriteString(z.Error.Desc)
+	if err != nil {
+		err = msgp.WrapError(err, "Error", "Desc")
+		return
+	}
+	err = z.Result.EncodeMsg(en)
+	if err != nil {
+		err = msgp.WrapError(err, "Result")
+		return
+	}
+	return
+}
+
+// MarshalMsg implements msgp.Marshaler
+func (z *Response) MarshalMsg(b []byte) (o []byte, err error) {
+	o = msgp.Require(b, z.Msgsize())
+	// array header, size 3
+	o = append(o, 0x93)
+	o = msgp.AppendUint32(o, z.MsgId)
+	// array header, size 2
+	o = append(o, 0x92)
+	o = msgp.AppendInt(o, z.Error.Code)
+	o = msgp.AppendString(o, z.Error.Desc)
+	o, err = z.Result.MarshalMsg(o)
+	if err != nil {
+		err = msgp.WrapError(err, "Result")
+		return
+	}
+	return
+}
+
+// UnmarshalMsg implements msgp.Unmarshaler
+func (z *Response) UnmarshalMsg(bts []byte) (o []byte, err error) {
+	var zb0001 uint32
+	zb0001, bts, err = msgp.ReadArrayHeaderBytes(bts)
+	if err != nil {
+		err = msgp.WrapError(err)
+		return
+	}
+	if zb0001 != 3 {
+		err = msgp.ArrayError{Wanted: 3, Got: zb0001}
+		return
+	}
+	z.MsgId, bts, err = msgp.ReadUint32Bytes(bts)
+	if err != nil {
+		err = msgp.WrapError(err, "MsgId")
+		return
+	}
+	var zb0002 uint32
+	zb0002, bts, err = msgp.ReadArrayHeaderBytes(bts)
+	if err != nil {
+		err = msgp.WrapError(err, "Error")
+		return
+	}
+	if zb0002 != 2 {
+		err = msgp.ArrayError{Wanted: 2, Got: zb0002}
+		return
+	}
+	z.Error.Code, bts, err = msgp.ReadIntBytes(bts)
+	if err != nil {
+		err = msgp.WrapError(err, "Error", "Code")
+		return
+	}
+	z.Error.Desc, bts, err = msgp.ReadStringBytes(bts)
+	if err != nil {
+		err = msgp.WrapError(err, "Error", "Desc")
+		return
+	}
+	bts, err = z.Result.UnmarshalMsg(bts)
+	if err != nil {
+		err = msgp.WrapError(err, "Result")
+		return
+	}
+	o = bts
+	return
+}
+
+// Msgsize returns an upper bound estimate of the number of bytes occupied by the serialized message
+func (z *Response) Msgsize() (s int) {
+	s = 1 + msgp.Uint32Size + 1 + msgp.IntSize + msgp.StringPrefixSize + len(z.Error.Desc) + z.Result.Msgsize()
+	return
+}

internal/gotelem/rpc_msg_gen_test.go

@@ -0,0 +1,462 @@
+package gotelem
+
+// Code generated by github.com/tinylib/msgp DO NOT EDIT.
+
+import (
+	"bytes"
+	"testing"
+
+	"github.com/tinylib/msgp/msgp"
+)
+
+func TestMarshalUnmarshalNotification(t *testing.T) {
+	v := Notification{}
+	bts, err := v.MarshalMsg(nil)
+	if err != nil {
+		t.Fatal(err)
+	}
+	left, err := v.UnmarshalMsg(bts)
+	if err != nil {
+		t.Fatal(err)
+	}
+	if len(left) > 0 {
+		t.Errorf("%d bytes left over after UnmarshalMsg(): %q", len(left), left)
+	}
+
+	left, err = msgp.Skip(bts)
+	if err != nil {
+		t.Fatal(err)
+	}
+	if len(left) > 0 {
+		t.Errorf("%d bytes left over after Skip(): %q", len(left), left)
+	}
+}
+
+func BenchmarkMarshalMsgNotification(b *testing.B) {
+	v := Notification{}
+	b.ReportAllocs()
+	b.ResetTimer()
+	for i := 0; i < b.N; i++ {
+		v.MarshalMsg(nil)
+	}
+}
+
+func BenchmarkAppendMsgNotification(b *testing.B) {
+	v := Notification{}
+	bts := make([]byte, 0, v.Msgsize())
+	bts, _ = v.MarshalMsg(bts[0:0])
+	b.SetBytes(int64(len(bts)))
+	b.ReportAllocs()
+	b.ResetTimer()
+	for i := 0; i < b.N; i++ {
+		bts, _ = v.MarshalMsg(bts[0:0])
+	}
+}
+
+func BenchmarkUnmarshalNotification(b *testing.B) {
+	v := Notification{}
+	bts, _ := v.MarshalMsg(nil)
+	b.ReportAllocs()
+	b.SetBytes(int64(len(bts)))
+	b.ResetTimer()
+	for i := 0; i < b.N; i++ {
+		_, err := v.UnmarshalMsg(bts)
+		if err != nil {
+			b.Fatal(err)
+		}
+	}
+}
+
+func TestEncodeDecodeNotification(t *testing.T) {
+	v := Notification{}
+	var buf bytes.Buffer
+	msgp.Encode(&buf, &v)
+
+	m := v.Msgsize()
+	if buf.Len() > m {
+		t.Log("WARNING: TestEncodeDecodeNotification Msgsize() is inaccurate")
+	}
+
+	vn := Notification{}
+	err := msgp.Decode(&buf, &vn)
+	if err != nil {
+		t.Error(err)
+	}
+
+	buf.Reset()
+	msgp.Encode(&buf, &v)
+	err = msgp.NewReader(&buf).Skip()
+	if err != nil {
+		t.Error(err)
+	}
+}
+
+func BenchmarkEncodeNotification(b *testing.B) {
+	v := Notification{}
+	var buf bytes.Buffer
+	msgp.Encode(&buf, &v)
+	b.SetBytes(int64(buf.Len()))
+	en := msgp.NewWriter(msgp.Nowhere)
+	b.ReportAllocs()
+	b.ResetTimer()
+	for i := 0; i < b.N; i++ {
+		v.EncodeMsg(en)
+	}
+	en.Flush()
+}
+
+func BenchmarkDecodeNotification(b *testing.B) {
+	v := Notification{}
+	var buf bytes.Buffer
+	msgp.Encode(&buf, &v)
+	b.SetBytes(int64(buf.Len()))
+	rd := msgp.NewEndlessReader(buf.Bytes(), b)
+	dc := msgp.NewReader(rd)
+	b.ReportAllocs()
+	b.ResetTimer()
+	for i := 0; i < b.N; i++ {
+		err := v.DecodeMsg(dc)
+		if err != nil {
+			b.Fatal(err)
+		}
+	}
+}
+
+func TestMarshalUnmarshalRPCError(t *testing.T) {
+	v := RPCError{}
+	bts, err := v.MarshalMsg(nil)
+	if err != nil {
+		t.Fatal(err)
+	}
+	left, err := v.UnmarshalMsg(bts)
+	if err != nil {
+		t.Fatal(err)
+	}
+	if len(left) > 0 {
+		t.Errorf("%d bytes left over after UnmarshalMsg(): %q", len(left), left)
+	}
+
+	left, err = msgp.Skip(bts)
+	if err != nil {
+		t.Fatal(err)
+	}
+	if len(left) > 0 {
+		t.Errorf("%d bytes left over after Skip(): %q", len(left), left)
+	}
+}
+
+func BenchmarkMarshalMsgRPCError(b *testing.B) {
+	v := RPCError{}
+	b.ReportAllocs()
+	b.ResetTimer()
+	for i := 0; i < b.N; i++ {
+		v.MarshalMsg(nil)
+	}
+}
+
+func BenchmarkAppendMsgRPCError(b *testing.B) {
+	v := RPCError{}
+	bts := make([]byte, 0, v.Msgsize())
+	bts, _ = v.MarshalMsg(bts[0:0])
+	b.SetBytes(int64(len(bts)))
+	b.ReportAllocs()
+	b.ResetTimer()
+	for i := 0; i < b.N; i++ {
+		bts, _ = v.MarshalMsg(bts[0:0])
+	}
+}
+
+func BenchmarkUnmarshalRPCError(b *testing.B) {
+	v := RPCError{}
+	bts, _ := v.MarshalMsg(nil)
+	b.ReportAllocs()
+	b.SetBytes(int64(len(bts)))
+	b.ResetTimer()
+	for i := 0; i < b.N; i++ {
+		_, err := v.UnmarshalMsg(bts)
+		if err != nil {
+			b.Fatal(err)
+		}
+	}
+}
+
+func TestEncodeDecodeRPCError(t *testing.T) {
+	v := RPCError{}
+	var buf bytes.Buffer
+	msgp.Encode(&buf, &v)
+
+	m := v.Msgsize()
+	if buf.Len() > m {
+		t.Log("WARNING: TestEncodeDecodeRPCError Msgsize() is inaccurate")
+	}
+
+	vn := RPCError{}
+	err := msgp.Decode(&buf, &vn)
+	if err != nil {
+		t.Error(err)
+	}
+
+	buf.Reset()
+	msgp.Encode(&buf, &v)
+	err = msgp.NewReader(&buf).Skip()
+	if err != nil {
+		t.Error(err)
+	}
+}
+
+func BenchmarkEncodeRPCError(b *testing.B) {
+	v := RPCError{}
+	var buf bytes.Buffer
+	msgp.Encode(&buf, &v)
+	b.SetBytes(int64(buf.Len()))
+	en := msgp.NewWriter(msgp.Nowhere)
+	b.ReportAllocs()
+	b.ResetTimer()
+	for i := 0; i < b.N; i++ {
+		v.EncodeMsg(en)
+	}
+	en.Flush()
+}
+
+func BenchmarkDecodeRPCError(b *testing.B) {
+	v := RPCError{}
+	var buf bytes.Buffer
+	msgp.Encode(&buf, &v)
+	b.SetBytes(int64(buf.Len()))
+	rd := msgp.NewEndlessReader(buf.Bytes(), b)
+	dc := msgp.NewReader(rd)
+	b.ReportAllocs()
+	b.ResetTimer()
+	for i := 0; i < b.N; i++ {
+		err := v.DecodeMsg(dc)
+		if err != nil {
+			b.Fatal(err)
+		}
+	}
+}
+
+func TestMarshalUnmarshalRequest(t *testing.T) {
+	v := Request{}
+	bts, err := v.MarshalMsg(nil)
+	if err != nil {
+		t.Fatal(err)
+	}
+	left, err := v.UnmarshalMsg(bts)
+	if err != nil {
+		t.Fatal(err)
+	}
+	if len(left) > 0 {
+		t.Errorf("%d bytes left over after UnmarshalMsg(): %q", len(left), left)
+	}
+
+	left, err = msgp.Skip(bts)
+	if err != nil {
+		t.Fatal(err)
+	}
+	if len(left) > 0 {
+		t.Errorf("%d bytes left over after Skip(): %q", len(left), left)
+	}
+}
+
+func BenchmarkMarshalMsgRequest(b *testing.B) {
+	v := Request{}
+	b.ReportAllocs()
+	b.ResetTimer()
+	for i := 0; i < b.N; i++ {
+		v.MarshalMsg(nil)
+	}
+}
+
+func BenchmarkAppendMsgRequest(b *testing.B) {
+	v := Request{}
+	bts := make([]byte, 0, v.Msgsize())
+	bts, _ = v.MarshalMsg(bts[0:0])
+	b.SetBytes(int64(len(bts)))
+	b.ReportAllocs()
+	b.ResetTimer()
+	for i := 0; i < b.N; i++ {
+		bts, _ = v.MarshalMsg(bts[0:0])
+	}
+}
+
+func BenchmarkUnmarshalRequest(b *testing.B) {
+	v := Request{}
+	bts, _ := v.MarshalMsg(nil)
+	b.ReportAllocs()
+	b.SetBytes(int64(len(bts)))
+	b.ResetTimer()
+	for i := 0; i < b.N; i++ {
+		_, err := v.UnmarshalMsg(bts)
+		if err != nil {
+			b.Fatal(err)
+		}
+	}
+}
+
+func TestEncodeDecodeRequest(t *testing.T) {
+	v := Request{}
+	var buf bytes.Buffer
+	msgp.Encode(&buf, &v)
+
+	m := v.Msgsize()
+	if buf.Len() > m {
+		t.Log("WARNING: TestEncodeDecodeRequest Msgsize() is inaccurate")
+	}
+
+	vn := Request{}
+	err := msgp.Decode(&buf, &vn)
+	if err != nil {
+		t.Error(err)
+	}
+
+	buf.Reset()
+	msgp.Encode(&buf, &v)
+	err = msgp.NewReader(&buf).Skip()
+	if err != nil {
+		t.Error(err)
+	}
+}
+
+func BenchmarkEncodeRequest(b *testing.B) {
+	v := Request{}
+	var buf bytes.Buffer
+	msgp.Encode(&buf, &v)
+	b.SetBytes(int64(buf.Len()))
+	en := msgp.NewWriter(msgp.Nowhere)
+	b.ReportAllocs()
+	b.ResetTimer()
+	for i := 0; i < b.N; i++ {
+		v.EncodeMsg(en)
+	}
+	en.Flush()
+}
+
+func BenchmarkDecodeRequest(b *testing.B) {
+	v := Request{}
+	var buf bytes.Buffer
+	msgp.Encode(&buf, &v)
+	b.SetBytes(int64(buf.Len()))
+	rd := msgp.NewEndlessReader(buf.Bytes(), b)
+	dc := msgp.NewReader(rd)
+	b.ReportAllocs()
+	b.ResetTimer()
+	for i := 0; i < b.N; i++ {
+		err := v.DecodeMsg(dc)
+		if err != nil {
+			b.Fatal(err)
+		}
+	}
+}
+
+func TestMarshalUnmarshalResponse(t *testing.T) {
+	v := Response{}
+	bts, err := v.MarshalMsg(nil)
+	if err != nil {
+		t.Fatal(err)
+	}
+	left, err := v.UnmarshalMsg(bts)
+	if err != nil {
+		t.Fatal(err)
+	}
+	if len(left) > 0 {
+		t.Errorf("%d bytes left over after UnmarshalMsg(): %q", len(left), left)
+	}
+
+	left, err = msgp.Skip(bts)
+	if err != nil {
+		t.Fatal(err)
+	}
+	if len(left) > 0 {
+		t.Errorf("%d bytes left over after Skip(): %q", len(left), left)
+	}
+}
+
+func BenchmarkMarshalMsgResponse(b *testing.B) {
+	v := Response{}
+	b.ReportAllocs()
+	b.ResetTimer()
+	for i := 0; i < b.N; i++ {
+		v.MarshalMsg(nil)
+	}
+}
+
+func BenchmarkAppendMsgResponse(b *testing.B) {
+	v := Response{}
+	bts := make([]byte, 0, v.Msgsize())
+	bts, _ = v.MarshalMsg(bts[0:0])
+	b.SetBytes(int64(len(bts)))
+	b.ReportAllocs()
+	b.ResetTimer()
+	for i := 0; i < b.N; i++ {
+		bts, _ = v.MarshalMsg(bts[0:0])
+	}
+}
+
+func BenchmarkUnmarshalResponse(b *testing.B) {
+	v := Response{}
+	bts, _ := v.MarshalMsg(nil)
+	b.ReportAllocs()
+	b.SetBytes(int64(len(bts)))
+	b.ResetTimer()
+	for i := 0; i < b.N; i++ {
+		_, err := v.UnmarshalMsg(bts)
+		if err != nil {
+			b.Fatal(err)
+		}
+	}
+}
+
+func TestEncodeDecodeResponse(t *testing.T) {
+	v := Response{}
+	var buf bytes.Buffer
+	msgp.Encode(&buf, &v)
+
+	m := v.Msgsize()
+	if buf.Len() > m {
+		t.Log("WARNING: TestEncodeDecodeResponse Msgsize() is inaccurate")
+	}
+
+	vn := Response{}
+	err := msgp.Decode(&buf, &vn)
+	if err != nil {
+		t.Error(err)
+	}
+
+	buf.Reset()
+	msgp.Encode(&buf, &v)
+	err = msgp.NewReader(&buf).Skip()
+	if err != nil {
+		t.Error(err)
+	}
+}
+
+func BenchmarkEncodeResponse(b *testing.B) {
+	v := Response{}
+	var buf bytes.Buffer
+	msgp.Encode(&buf, &v)
+	b.SetBytes(int64(buf.Len()))
+	en := msgp.NewWriter(msgp.Nowhere)
+	b.ReportAllocs()
+	b.ResetTimer()
+	for i := 0; i < b.N; i++ {
+		v.EncodeMsg(en)
+	}
+	en.Flush()
+}
+
+func BenchmarkDecodeResponse(b *testing.B) {
+	v := Response{}
+	var buf bytes.Buffer
+	msgp.Encode(&buf, &v)
+	b.SetBytes(int64(buf.Len()))
+	rd := msgp.NewEndlessReader(buf.Bytes(), b)
+	dc := msgp.NewReader(rd)
+	b.ReportAllocs()
+	b.ResetTimer()
+	for i := 0; i < b.N; i++ {
+		err := v.DecodeMsg(dc)
+		if err != nil {
+			b.Fatal(err)
+		}
+	}
+}

internal/gotelem/rpc_msg_test.go

@@ -0,0 +1,54 @@
+package gotelem
+
+import (
+	"reflect"
+	"testing"
+
+	"github.com/tinylib/msgp/msgp"
+)
+
+func Test_parseRPC(t *testing.T) {
+	type args struct {
+		raw msgp.Raw
+	}
+	tests := []struct {
+		name    string
+		args    args
+		want    interface{}
+		wantErr bool
+	}{
+		// TODO: Add test cases.
+	}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			got, err := parseRPC(tt.args.raw)
+			if (err != nil) != tt.wantErr {
+				t.Errorf("parseRPC() error = %v, wantErr %v", err, tt.wantErr)
+				return
+			}
+			if !reflect.DeepEqual(got, tt.want) {
+				t.Errorf("parseRPC() = %v, want %v", got, tt.want)
+			}
+		})
+	}
+}
+
+func Test_getMsgType(t *testing.T) {
+	type args struct {
+		b []byte
+	}
+	tests := []struct {
+		name string
+		args args
+		want RPCType
+	}{
+		// TODO: Add test cases.
+	}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			if got := getMsgType(tt.args.b); got != tt.want {
+				t.Errorf("getMsgType() = %v, want %v", got, tt.want)
+			}
+		})
+	}
+}

internal/xbee/at.go

@@ -138,6 +138,7 @@ func encodeRemoteATCommand(at ATCmd, idx uint8, queued bool, destination uint64)
 
 // let's actually define some AT commands now.
 
+// TODO: should we just use a function.
 // the AT command for the ID (Network ID).
 // the network identifier is used to communicate with other devices. It must match.
 type ATCmdID struct {